1. Field of the Invention
This invention relates to compositions of hydrocarbons. Particularly, this invention relates to additives which reduce the tendency of certain hydrocarbons to generate and hold static electric charges.
2. Description of the Prior Art
Generation of static electricity on hydrocarbons is very dangerous. Numberous explosions and fires have been caused by sparks resulting from static charges generated on hydrocarbons. Commonly, static charges are generated on materials which have very low conductivities. Low conductivities result from the general purity of many hydrocarbons. Commonly, hydrocarbons are materials which have low conductivities and are susceptible to static charge generation. Aviation jet fuel, for example, commonly can have conductivity of less than one picosiemen. A minimum conductivity of 50 picosiemens is generally necessary to dissipate the static charges generated on the hydrocarbon.
Static charges can be built up during storage and transfer of fluid hydrocarbons in metal pipes and containers. If the conductivity of the hydrocarbon is high, the static charge dissipates quickly. When conductivities are low, the static charge dissipates very slowly. Sparks occur when the static is generated faster than the charge can be dissipated. Once the voltage of the static charge passes a certain level, called the "breakdown potential," about 30,000 volts, a spark occurs.
A number of ashless antistatic agents are known. Many antistatic agents are complex mixtures of amines, hydrocarbons, sulfur compounds, and assorted polymers. Other antistatic agents are copolymers of alphaolefins, sulfur dioxide, and maleic anhydride. Still other antistatic additives are copolymers of alpha olefins and sulfur dioxide combined with polyamines.
Many antistatic agents are unstable chemicals which decompose and lose the antistatic effect. Other antistatic agents are commonly adsorbed out of the fuel by container walls, thus dangerously lowering the hydrocarbon conductivity. Typical antistatic additives are used at concentrations from 0.1 to 10 ppm based on the hydrocarbon. Many antistatic additives are produced from expensive chemical intermediates which are wasted by poor product yields. Thus a need for an antistatic agent which has improved properties was needed.
Numerous materials have been suggested in the prior art as antistatic agents. Examples of these agents are found in U.S. Pat. Nos. 3,844,732, 3,917,466, and 3,991,079. U.S. Pat. No. 3,844,732 discloses a fuel composition comprising a major amount of a liquid hydrocarbonaceous fuel and in an amount sufficient to provide engine cleanliness a hydrocarbylaminomethylene-sulfonic acid, wherein said hydrocarbyl group contains at least 30 carbon atoms.
U.S. Pat. No. 3,991,079 discloses compositions made by reaction (A) an acylated amino hydrocarbyl sulfonic acid having an acyl portion containing a substantially saturated hydrocarbyl substituted substituent at least about 12 carbon atoms and bonded to the amino hydrocarbyl sulfonic acid through an acyl, acylimidoyl or acyloxy linkage, (B) a heterocyclic reagent such as an epoxide, episulfide or aziridine and (C) an amino compound having about 1 to about 400 carbon atoms or an organo-sulfide having 2 to about 50 carbon atoms are useful in fuels and lubricants as dispersants, anti-static agents and corrosion inhibitors.
U.S. Pat. No. 3,917,466 discloses anitstatic additive compositions for hydrocarbon fuels, the compositions comprising olefin-sulfur dioxide copolymers in combination with polymeric polyamines.
An object of the invention is to produce an antistatic agent additive which is stable in fuels. A further object of the invention is to have an additive which is effective at concentrations of less than 10 ppm. Still another object of the invention is a reaction of common industrial chemicals which proceeds to total conversion of starting materials to additive.